Production of superior solvents



July 28, 1942- J. E. HARVEY, JR 2,291,328

PRODUCTION OF SUPERIOR SOLVENTS Filed July 15, 1940 Patented July 28, 1942 PRODUCTION OF SUPERIOR SOLVENTS J acquelin E. Harvey, Jr., Atlanta, Ga., assgnor of one-half to Southern Wood Preserving Company, East Point, Ga., a corporation of Georgia Application July 13, 1940, Serial No. 345,445

1 Claim.

The present invention relates to the production o-f valuable solvents from tars and fractions thereof of aromatic content, crude and/or refined.

An object of the present invention is the production of superior solvents from tars, or fractions thereof, said production being characterized by being effected in step-wise manner.

A further object of the present invention is Ia provision of increased boiling range and increased solvency.

Further object of the present invention is the production of solvents, the characteristics of which are, among other things, dependent upon hydrogen supply.

Other objects of the present invention will be apparent from the following disclosures.

Suitable starting materials of the present invention include tars and fractions thereof derived from coal, wood, petroleum or gas, as for instance coke oven tar, gas house tar, water gas tar, and tars of aromatic content derived from petroleum or fractions thereof; tars of aromatic content produced by cracking hydrocarbons or high boiling fractions resulting from the action of hydrogen on hydrocarbons; tars of aromatic content resulting from catalytic action on hydrocarbons, including polymerization; high boiling aromatic extracts of carbonaceous substances; high boiling hydrocarbons of olenic and naphthenic content; tars and fractions thereof of aromatic content.

Especially attractive as starting material is high temperature coke oven tar which is available in large quantities at low price.

The present invention may be broadly viewed as providing a process for the production of solvents by subjecting the starting material, in step-wise manner, to the controlled action of hydrogen, while contacting a catalytic material chosen from the group consisting of halids, halogens and derivatives thereof, whereby to produce solvents of increased boiling range and enhanced solvency, as hereinafter described.

The starting materials of the present process are characterized by content of oXygenated organic compounds.

In my copending application Serial No. 345,- 439, dated July 13, 1940, is described a method for the substantially total conversion of tars and fractions thereof into solvents of superior quality, said conversion being characterized by subjecting the starting material in step-wise manner to the controlled action of hydrogen.

It has been discovered that the process described in said copending application can be improved upon by the specic provision of means of influencing the decomposition of said oxygenated organic compounds contained in the starting material.

Thus, the present invention provides a method for the production of solvents from tars or fractions thereof of oxygen content, said production being characterized by subjecting the starting materi-al to the controlled step-wise action of hydrogen while contacting a catalytic material selected from the group consisting of halids, halogens, and derivatives thereof. The provision of said catalytic material influences the decomposition of the oxygenated organic compounds contained in the starting material while under the action of hydrogen, to the end that the induction and production of the solvents of the present invention is enhanced.

The invention will be understood fro-m the following description of illustrative steps comprising various methods of securing the objects of the invention, when read in connection with the y'accompanying' drawing wherein the ligure is a diagrammatic sketch of an apparatus for carrying out a form of the process of the invention and wherein the nature of the step carried `out in each chamber and the contents thereof are indicated by legend The following examples will serve to illustrate several modes of practicing the present invention.

Example I.-A coal tar boiling substantially 3% at 210 C. was passed through a high pressure reaction chamber at 400 C. and 200 atmospheres pressure. Catalyst was tinsulde and iodoform, time of contact 1 hour and gas flow suiiicient to provide a beneficiated tar having lowered solvency, boiling range, specific gravity and viscosity. The thus beneiiciated tar was distilled to 315 C. to recover in the order of 30% of the beneciated tar as a distillate. The distillate was then passed through -a high pressure reaction vessel at 475 C. and a pressure of 250 atmospheres with flow of hydrogen so controlled as to provide a solvent, as compared to its intermediate parent material, having an increased boiling range, specific gravity, and solvency,

Example II.A residue from coal tar boiling substantially 3% lat 380 C., Conradson carbon 14.5 and specic gravity 1.208 was passed through a high pressure reaction chamber at 410 C. and 300 atmosphere pressure; time of contact substantially 1 hour. Catalyst was molybdenum sulfide and tin chloride. Gas flow was sufficient to provide a beneficiated tar fraction having a specific gravity of less than 1.06, a Conradson carbon of in the order of 4 fand a lower solvency than the starting material. The thus beneciated t-ar fraction was stripped to 350 C., whereby to provide in the order of 65% of the beneciated material as a distillate. The distillate was then passed through a high pressure reactor at 460 C. and 300 atmospheres pressure,

while contacting a catalyst consisting of molyb-V denum-tin sulfide with fiow of hydrogen so controlled as to induce a solvent. having,l ascompared to the intermediate parent materiahian increased specific gravity, boiling range andsol-L vency.

The solvents so produced maybe fractionated to provide solvents and plastioizers of anyvboiling range, as for instance: C.

Benzol .7B-120 Toluol 1GO-150 Hi-iasn naphtha 15G-200 Plasticizers .1GO-360 Y Or, the induced solvents mayinclude lower Aboilingv range than noted above.

The solvents Vof the presenteinvention serve as good substitutes for the commercial solvents noted-in the above tabular data.

In the foregoing examples, it will be noted that the present process providesa method for contacting heavy hydrocarbons with hydrogen in .the presence of a catalyst Vcontaining a material selected from a group` consisting of halogens, halids and'derivatives thereof, whereby to produce a productv of lowered solvency, specific gravto-an intermediate Yparent material, as heretofore disclosed; the-step-wise action of hydrogen being characterized by first providing hydrogen flow that depolymerizes ring multiplicities thereby inducing lowered specific gravity, boiling range and solvency, and second, by providing hydrogen in flow that increasesA specific-gravity, boiling range and solvency; afmaterial influencing oxygenation-product decomposition being present in at least oneof said stages.

, The aforenamed step-wise action of hydrogen thus provides a method for securing solvents of but must first be subjected to the controls of the present process wherein hydrogen flow, among other things, depolymerizes said molecular complexes.

The depolymerized or partially depolymerized tar or fraction thereof, is then stripped of a percentage of its low ends whereby to provide as a distillate the intermediate parent material of the solvents of increased boiling range and solvency. rEhe residue incidental to said stripping may be- `cause of its depolymerized or partially depolymerized condition serve as material for recycle, with Aorwithout the addition of other starting material to the end that conversion of the startingmaterial may approach volume for volume of said starting material into solvents of the present invention, neglecting manufacturing and gas loss.

In the conversion of the starting material, partially or approaching unit, into solvents of the Vpresent process,.temperatures as low as 300 C.

may be used; pressure Yas lowfas atmospheres Y may be employed. However, temperatures and pressures of an increased range provide better commercial practicerof .the present invention. The time element is desirably that period which affords commercially `recoveries of theproducts of, and incidental to, the presentinvention.

Flows of hydrogenor hydrogen containing gas are usually heldin-excess 2,000 cubic feet perbarrel material treated. In the step-Wise application whereby to provide. the solvents of thepresent invention,` a few` trials when. using any of this starting materials willI determine the gas ow, when coordinated With thes'elected temperature and pressure conditions to aect aforesaid depolymerized conditions. l The gas flow in this instance may be-variable quantity because of the varying rangesof coordinated temperature and pressure that may -be selected. When using chosen coordination of Ytemperature and pressure a few trials will-'readily determine the gas flow that provides depolymerizingconditions tothe end that solvency, specific Y gravity, viscosity, and boiling range are lowered.

A few trials with any-of .the intermediate starting materials under chosen-coordination of temperature and pressurewilll readily determine the -Y desirable gas flow. For afgiven coordination of increased solvency and boiling rangefrom heavyor high boiling hydrocarbons of aromatic content, said highboilers characterized by the pres- Venceof ring Amultiplicitie's of great thermal susceptibility; and are further Vcharacterized by content of oxygenated organic compounds.

The starting materials of high carbon content, as for instance high temperature coke oven tar or fractions thereof, are characterizedY by, in their raw state, suclra percentage of high molecular complexes or polymerized products-that the solvents of the present inventiomthat is to say, solvents of increased boiling range and solvency are not possible of 'manufactureY directlyvtherefrom,

Vthe action -of hydrogen ini-accordance: with the present invention.

After the starting tar hasr been subjected to depolymerizing action, as aforesaid, the stripping step may be effected at any point selected Within a wide range to provide a cut capable of providing after further processing-substitutes for benzol, toluol, Xylol, naphthas, and/ or plasticizers.

Thus, the depolymerized starting material may be cut-accordingY to the need yat hand; said cut then being subjected to the action of hydrogen that increases solvency and'boilingrange.

The residues resulting-from any distillation step recited herein may be recycled for further solvent production.

In addition to aforementioned catalysts that inuence the decomposition of oxygenated organic compounds contained in the starting material, various catalysts effective in the presence of hydrogen may be used. Catalysts chosen from the sixth and eighth periodic groups are effective. Especially effective are chromium, molybdenum, vanadium, uranium, cobalt, copper, and their compounds, as for instance their suldes and/ or oxides; promoted or not; with or without small amounts of alkali acid or halogen or derivatives thereof; effective catalyst deposited on carriers, as for instance on gels, earths, carbon or the like; in various shapes, as for instance forms, extruded shapes or lengths, pellets, comminuted; mixed with other material effective in the presence of hydrogen or not; with or without the addition of material or materials effecting splitting.

When using catalyst it may be desirable at times to use a comminuted catalyst during the period of the process characterized by depolymerization; thereafter, and during the period characterized by increase in solvency and boiling points, to use a rigid catalyst.

By the terms multiplicity of rings, high molecular complexes and polymerized products are meant high boiling fractions of aromatic content, a portion of which at least, may be viewed as ring multiples; or, said terms, any or all, may be used to describe high boiling fractions of the starting material which because of high carbon content are especially susceptible to thermal degradation. All high boiling fractions of the starting material contain oxygenated compounds and their depolymerization is enhanced by the addition of catalytic material that influences decomposition of said oxygenated compounds.

When subjecting high boiling fractions of aforenamed materials to the process of the present invention, it may be desirable prior to the depolymerizing step to at least partially depolymerize the molecular complexes by use of a solvent. Said solvent may be added in small amounts, or up to volume for volume, or more may be used. Refractory solvents are desirable, but others more susceptible to the reactions inherent in and to the present process are usable.

Concerning solvents, it may be said that tar, as for instance high temperature coke oven tar, comprises high molecular complexes dissolved, cut back or depolymerized with a solvent, said solvent being the lower boiling fractions of said tar.

The depolymerizing action of hydrogen, as aforestated, may be effected in one or more cycles or chambers, with or Without releasing the pressure and with or without variation of process controls, including changes in either temperature, pressure and/or gas control; the final action of hydrogen according to the present invention may be effected in one or more cycles or chambers with or without releasing pressure and with or without variation of process control, including changes in either temperature, pressure and/or gas iiow.

Various modes of practicing the present invention are possible; as for instance the depolymerized starting material may be stripped as for instance by gas movement; the low ends thus stripped may then with or without releasing pressure be subjected to the action of hydrogen that increases solvency and boiling points. Or the desired material may be obtained by partial release of pressure which corresponds to the fractional recovery desired or predetermined.

The process may be practiced in single high pressure chamber, a series thereof, parallelism thereof, including a multiplicity thereof.

The solvent of the present invention may, as aforestated, be fractionated to provide solvents of various boiling ranges, and in an instance where said solvents are processed from a deep cut on the depolymerized material, the highest boiling fraction of said deep cut may serve after further processing as plasticizing oils or the like.

From the foregoing disclosures it will be seen that the present invention provides a method for the production of solvents, characterized by subjecting oxygenated tar fractions boiling substantially above C. to the action of hydrogen while contacting a catalyst containing a material selected from a group consisting of halids, halogens, and derivatives thereof, whereby to enhance the action of depolymerizing high molecular complexes and lower specific gravity, viscosity, solvency and boiling range; stripping therefrom a lower boiling fraction and subjecting said low boiling fraction to the action of hydrogen that induces solvency.

The expressions increased boiling points and increased boiling range are used interchangeably and mean that the material so described has a widened boiling range, as for instance, having increased low boiling ends.

Minor changes may be made within the Scope of the appended claims without departing from the spirit of the invention. In the claims afxed to this specification no selection of any particular modification is intended to the exclusion of other modifications thereof.

I claim:

In the production of solvents from a mixture of high temperature coal tar fractions, the process which comprises: subjecting said mixture of tar fractions to the action of a ow of hydrogen in excess of 10,000 cubic feet per barrel material treated while contacting a catalyst selected from the group consisting of halogens, halids and derivatives thereof; carrying on the process at a pressure and temperature not substantially lower than 50 atmospheres and 300 C., respectively, and for such a length of time as to provide a material of lowered specific gravity and viscosity; stripping low boiling fractions from the beneciated material, said low boiling fractions representing at least about 30% of the beneciated material but boiling not higher than about 350 C.; and subjecting said low boiling material in substantial entirety to the action of a ow of hydrogen chosen from the range not in excess of 8,000 cubic feet per barrel material treated at a temperature and pressure in excess of about 460 C. and 50 atmospheres, respectively, for such a period of time as to provide a newly formed material of increased specific gravity.

JACQUELIN E. HARVEY, JR. 

